Method of treating pulverized fuel



- H..E. H. POMEROY.

METHOD 10F TREATING PULVEIHZED F'UE'L.

APPIT'YICATION Fl LED DEC. :4. ml.

Patentd-July. 18, 1921 2 SHEEE S SH'EET l.

iNVE-NTOF! ATTORNEY R. E. HI POMEROY.

METHOD OF TREATING PULVERIZED FUEL.

APPLICATION FILED DEC I4, 1921 Patented July 18, 11922.

2 SHEETS-SHEET 2.

IIA'IIIIIIII INVENTOR STATES RALPH E. H. POMEROY, OF CANTON, OHIO.

' METHOD OF TREATING PULVERIZED FUEL.

To all whomc't may concern Be it known that I, RALPH E. H. POME- nor,residing at Canton, in the county of Stark andState of Ohio, a citizenof the United States, have invented or discovered certain new and usefulImprovements in Methods of Treating Pulverized Fuel, of whichimprovements the following is a speci fication.

The invention described herein relates to the removal of fine or reducedmaterial by imparting such movements to a. loose mass Consisting ofpieces of frangible material (as coal and hard bodies, as metal balls)that the elements of the mass willhave such movements relative to oneanother that the reduction will, be effected in part by the impact ofthe elements with one another, and in part by abrasion or the rubbing ofthe elements against one another. \Vhile the invention described hereincanbe practiced by the use of many different types of mills operating inthe manner above described, the invention will be described inconnection with a familiar type known as the tumbling box, ball milltype, pipe mill, etc., and consist'ing of a rotatable drum containing aplurality of balls, rods, pipes, cobble stones, or other hard bodies.

It has been the practice heretofore to so construct and operate thistype of mill that the fine is discharged either through openings orscreens in the periphery of the drum, or by means of a current of airentering through one trunnion and escaping laden with dust or fineparticles through the othertrunnion. In some cases, the removal of thefine particles in the first of the above types,

. has been accelerated by currents of air entering through one trunnionand passing out through the peripheral openings or screens. As thelarger pieces of the material are more efiiciently affected by gravityand centrifugal force than the finer particles, these larger particleswill form a very large per cent of the portion of the charge in contactwith the inner periphery of the drum,

' and being formed of pieces too large to pass through the screen orother discharge openafter it has been reduced ings, reduce the dischargeareas of the openings or screens, and hence material is retained in thedrum for a considerable time to the desired degree of fineness.

In the type of mills employing currents of air for the removal or thepulverized mate- Patented July 18, 1922.

Application filed December 14, 1921 Serial No. 522,360.

rial, the current will flow in a substantially straight line from onetrunnion to the other, and as the charge is below or to one side of themain line of flow pulverized material as is thrown into the current bythe agitation of the chargewill be carried from the mill, andconsequently this method of removing fine particles is very inefiicient.

It is characteristic of the methods heretofore practiced that thesegregation of the fine and coarse material 'hasbeen due to the gradualworking of the fine particles outwardly 'or inwardly through the chargein the mill as the elements of such charge move relative to each otherand that in none of these methods was there any attempt to re movematerial from the mass practically as soon as the desired degree offineness had been attained.

The invent-ion described herein has for its object the removal ofmaterial when it has attained the desired degree of fineness from a massconsisting of-material to be treated and the pulverizing elements bymeans of currents ofair passing through the mass from the denser to theless dense or compacted. portions and in a direction in which the finerparticles are moved by the work- I ing or agitation of the elements ofthe mass by the rotation of the drum. It is a further object of theinventionto effect within the mill a grading of the materials forcedfrom the mass by the air currents whereby only the material of thedesired fineness is carried out of the mill and the coarser materialreturned to the charge being reduced. The invention is hereinafter morefully described and claimed.

In the accompanying drawings forming adrum through either or bothtrunnions, said drum containing balls or other hard objects usuallyemgloyed in this type of pulverizing mill. charge is turned over andover and the material to be treated is broken up and pulverized of theair, only such n the rotation of the drum the partly by the impact ofthe balls and partly by abrasion of the balls on the material. Duringthe turning of the drum, portions of the charge adjacent to the innersurface of the drum are carried up until the force of gravity overcomesthe centrifugal tendency to press the charge outwardly. When portions ofthe charge reach this point. they will drop and roll down the innersurface of the charge. By the rotation' otthe drum all'parts of thecharge pass through this cycle of movements but there will always be atendency for the largerand heavier elements to move outwardly throughthe mass and collect against the drum. but the interstices between thelarger or coarser elements will be filled to a greater or less degree bythe finer. In order to remove the fine material. currents of air or jetsof air are directed inwardly through the charge by perforations in thepcriplnery of the drum. These inflowing jets of air will carry the linematerial out of the charge. into the space not occupied by thecharge.The dust laden air may pass out of the drum either through the trunnionopposite that through which the material was charged as shown in Figs. 1and 2. or through the ports or perforations in the periphery of the drumas shown in Fig. 3.

The fineness or grade of material carried out of the charge will bedependent upon the quantity and rate oi movement of the air passingthrough the charge. the greater the quantity. and the higher the rate offlow. the larger or coarser will be the particles removed and thegreater the quantity of material taken out of the charge. It will begenerally preferable to leliect a rapid removal of the material. biit asparticles larger than desired will probably be carried out. provision ismade for separatmg the particles of the desired grade from the coarserwithin the drum and carrying such desired product out of the drum whilethe coarse particles are returned to the charge undergoing reduction. Tothis end the ports or passages through which the air enters and throughwhich the dust laden air passes from the drum are so constructed andarranged that the air will enter the drum at an angle to the radii ofthe drum and have a cyclonic movement within the drum. the circularmovement being the reverse of the direction of rotation of the drum.'Ata suitable point in its circular movement the air passes out of thedrum through the passages in the periphery of the drum arranged at anangle preferably greater than 90 degrees to the path or rotation of theair in the drum. By properly proportioning the rate of How of theoutgoing air. only the particles of the desired degree of fineness willremain with the air. and pass out of the drum. while the larger pieceswill by reason of their 1110 163 of the shell.

tum pass beyond the outlets and be brought backto the tumbling mass forfurther reduction.

While as hereinbefore stated, the method described and claimed hereincan be carried out indifferent types of mills, the constructionsdescribed and claimed in applications Serial Numbers -ft7-l,tl79 and516,380, filed by me June 1st, 1920 and November 19, 1921, respectively,and also so far as is necessary for the purposes of this case, shown inFigs. l. 2, 3, and l have been found suitable.

in the construction shown herein the mill consists of a rotatable shell5 having its ends secured to heads (5 provided with trunnions T. In theconstruction shown in Figs. 1 to 3. inclusive. both trunnions are madehollow and provision is made for the feed of fuel through one of thesetrunnions as 7 while the opposite trunnion T is employed as an outletfor the air carrying the dust as hereinafter described. The trunnionsare mounted on fixed bearings R and the shell is driven by pinion E)engaging a gear wheel 10 secured to one of the heads of the shell. Asdescribed in said application a suitable quantity of loose grindingmaterial or deyiccs such as metal balls. cobble stones. rods or bars oihard material are charged into the shell or drum and operated for pulverizing the material for impact or rubbing. For convenience the termballs will be used as a generic term inclinling thereunder any and alldevices usually employed in'such a mill.

The shell is enclosed by a casing 12 closely fitting against the shellbut not with suflicient closeness to prevent the free rotation Theinterior surface of the shell is covered with a lining preferablycomposed of a series of longitudinal sections or liners 15 of metalextending substantially the full length of the shell and having passagesthereunder. the outer ends of which register withperforations formed inthe shell In constructions of mills shown in Figs. 1. Q and 3, where thematerial escapes from the shell 5 through the trunnion the enclosingcasing 12 is provided with an enlargement forming an air chamber 14, theportion of the casing forming this air chamber being preferablyadjustable peripherally of the shell and easing so that the point ofentrance of the air may be varied as re quired. In the constructionshown in Fig. 4 where the material passes from the shell through theperipheral openings the casing is provided with enlargements formingchambers 16 and 17 the former being the inlet chamber and the latter theoutlet chamber. The inlet chamber is preferably so located as describedin the application Serial Number 516,380, asto extend from a planeapproximately coincident with the horizontal diameter of the drum alongfor a suitable distance, as for example, a little further than thematerial would be carried in the rotation. of the drum, above thishorizontal plane. In other words, this inlet chamber preferably extendscircumferentially from about the point. where the charge in the shell.begins to loosen up to a point a little beyond that to which theelements of the mass move away from the surface of the.

shell. This chamber is provided with an air inlet which, in case air ata p-resssure above atmospheric is employed, is connected to a fan orother suitable air compressor. other chamber eitends preferably forabout one-fourth of the circumference of the shell and is.located sothat the air after passing through the charge can escape through theperforations in the shell into the chamber from whence it is carried bysuitable means to a point'of use.

I claim herein as my invention:

1. The method hereindescribed of removing material from a pulverizerwhich consists in imparting a rotary tumbling movement to aloose masscomposed of pieces of frangible material and balls of a more durable.material causing streams or jets of air to traverse said mass in adirection opposed to the direction of movement of the mass and carry thereduced particles from between the elements composing the mass.

2. The method herein described of removing material from a pulverizerwhich con sists in imparting a rotary tumbling movement to a loose masscomposed of pieces of frangible material and balls, directing streams orjets of air into said receptacle and through the loose mass in thezoneof The reduction whereby reduced particle's are removed trom betweenthe elements-composing the mass permitting the escapeulolf" theaircarrying the particles; from thejreceptacle and changing the directionofffioyvf of the air at the outlet from the receptacle "to ef feet asegregation of the fine particlesfrom the coarse particles- 3. Themethod herein described of.remcfln ing material from a pulverize'r whichcon! sists in enclosingin a suitable receptacle a loose mass composed'of.piecesiofftfrangible material and balls impartingarotary tumblingmovement to such mas's, causing currents of air to traversesaidz'massqin a direction opposed to the direction'of ro tation of themass,.whe'reby a circular movement is imparted to the air escaping fromthe mass, and causing the air and reduced material to pass out ofthechamber in a direction at an angle to the' circular moverelativelydense or in close grinding relation and will emerge through the lessdense portions of the mass. r

In testimony whereof, I have hereunto set my hand.

RALPH E. H. POMEROY.

